1. Field
One or more embodiments described herein relate to a display device.
2. Description of the Related Art
A variety of flat panel displays have been developed. Examples include liquid crystal displays, field emission displays, plasma display panels, and organic light emitting displays. An organic light emitting display uses organic light emitting diodes (OLEDs) to emit light based on a recombination of electrons and holes in an active layer. Displays of this type have fast response speeds and output clear images.
Different methods may be used to display gray scale values in an organic light emitting display. These methods include an analog driving method and a digital driving method.
An analog driving method displays gray scale values by changing the amplitude of current applied to the OLED based on a data signal. The changed amplitude of the current adjusts emission luminance of the OLED. Thus, in an analog driving method, the amplitude of a data signal applied to each pixel is controlled for the same emission time of the OLED, and the amplitude of a voltage or current supplied to the OLED is adjusted to thereby express light of a specific gray scale value.
A digital driving method displays gray scale values by controlling the emission time of the OLED in each pixel based on a data signal. In one type of digital driving method, current of a predetermined amplitude is applied to the OLED based on the amplitude of a voltage. The turn-on time of the OLED is controlled through an applied data signal when emission luminance of the OLED is constantly maintained. As a result, light is emitted at a specific gray scale value.